A known image forming apparatus that can perform double-sided printing includes an image forming device and a reverse path through which a sheet that has passed through the image forming device is re-conveyed to it. On the reverse path, a side registration guide is provided that changes a conveying direction, in which the sheet is conveyed, from vertical to horizontal, and also guides the sheet while correctly keeping the position of the sheet in its width direction.
The side registration guide has two guide surfaces. When the sheet passes between these guide surfaces, the conveying direction of the sheet is changed. The side registration guide also has a side wall that is contacted by one end of the sheet in the width direction. Since the side wall is inclined relative to the conveying direction of the sheet, the sheet is guided and its position in the width direction is correctly kept. The width direction is a direction orthogonal to the conveying direction of the sheet (that is, the scanning direction) and to the thickness direction of the sheet.